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    <title>Document</title>
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    <script>
      function Fn() {
        // Fn是函数
      }
      const fn = new Fn(); // Fn是构造函数  new返回的是实例对象
      console.log(Fn.prototype); // Fn是函数对象
      Fn.call({}); // Fn是函数对象


      $("#test"); // $是函数
      $.ajax(); // $是函数对象


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